The present invention relates to a static electricity eliminating apparatus and a static electricity eliminating method.
In daily life, for example, when one walks, static electricity occurs due to a friction between the person and his or her clothes. Further, most of floors, halls, lobbies and the like are covered with carpets, and when one walks on the carpet, static electricity occurs on his or her body. The static electricity is accumulated on a human body or the clothes as a static charge without being naturally discharged. As a result, when one touches a door to a room, a door to a house, a doorknob, up-down buttons of an elevator, a doorknob of an automobile, metallic furniture or the like, a charge (static electricity) charged in a human body and/or the clothes is rapidly discharged to cause an impact on the human body.
Further, electronic machines and tools such as personal computers and cellular phones use a number of integrated circuits and electronic parts. When one charged with static electricity comes close to the electronic machine or tool or touches it, electrostatic induction of a charge takes place in the electronic machine or tool in many cases. When a charge accumulated in the electronic machine or tool is discharged at once to be over the withstand voltage of the electronic part constituting the electronic machine or tool, a discharge voltage is sometimes over several kilovolts, so that such a high discharge voltage causes the electronic machine or tool to operate in error or to have a trouble.
As a method of alleviating an impact on a human body when a charge (static electricity) is discharged, generally, there is a method in which provided is a static electricity eliminating apparatus grounded (earthed) through a high-resistance circuit (more specifically, for example, a so-called surge-absorbing circuit including a resistor), and one touches the static electricity eliminating apparatus to flow the charge (static electricity) to the ground.
Concerning an electronic machine and tool, there can be a method in which a static electricity eliminating circuit comprising a combination of a coil or a resistor for suppressing a discharge current and a condenser or Zener diode for absorbing an electrostatic pulse is incorporated into the electronic machine or tool. For eliminating static electricity in a product charged, for example, by a friction during transportation (for example, a charged film or a charged electronic part), there is known a method using a static electricity eliminator according to an AC voltage applying method that generates ion gases for ionizing an atmosphere in the vicinity of the charged product by corona discharge.
JP-A-10-316321 (for example, in FIGS. 1 and 2 on page 3) discloses a constitution of an elevator hall touch panel, in which a static electricity absorbing plate is grounded through a high-resistance resistor. It is said that according to the technique disclosed in the above JP-A-10-316321, the voltage of static electricity is exerted on the resistor not instantly but over a long period of time as compared with the case where the resistor is not present, so that an impact on a human body can be alleviated.
JP-A-2001-35684 (for example, on page 2) discloses a method in which a metallic portion of a structure or a door of an automobile is grounded through a contact member. A so-called surge-absorbing circuit including a resistor is incorporated into a circuit to which static electricity is discharged, for easing an abrupt discharge.
JP-A-01-251598 (for example, on page 2) discloses a technique of allowing an electrically conductive substance to adhere to an electrically conductive fiber for removing static electricity without grounding.
JP-A-05-174376 (for example, on pages 2 and 4 and FIG. 1) discloses a method in which static electricity charged on a polyethylene terephthalate film (PET film) is neutralized by means of an ion-generating apparatus for applying a high voltage to an ion-generating electrode from a high voltage power source to ionize air.
JP-A-2000-262303 (for example, on page 1) discloses a product called a “wrist trap” as one measure to be taken against static electricity in a factory.
However, in a static electricity eliminating method using a conventional static electricity eliminating apparatus having a high-resistance resistor or an electrically conductive material intervened in a path through which a charge (static electricity) charged in clothes is discharged for easing an abrupt discharge, a discharge circuit is formed on condition that the discharge circuit is grounded, and a human body is part constituting the discharge circuit, so that a considerable impact is exerted on some persons during discharging. In the above method, inconveniently, one is required to touch the static electricity eliminating apparatus that is constantly grounded. Further, the charged state greatly differs depending upon persons, some persons are charged with static electricity a little, and some persons are charged greatly. With a static electricity eliminating method (grounding method) using a conventional static electricity eliminating apparatus, there are some cases where a person charged greatly cannot avoid an impact.
The method of incorporating a static electricity eliminating circuit into an electronic machine or tool involves a problem that it is required to constantly ground the static electricity eliminating circuit. Further, when an electronic machine or tool is grounded, it sometimes picks up a noise from the ground, so that a trouble may be caused on the operation of the electronic machine or tool. Cellular phones are widely spreading in recent years. However, it is difficult to ground a cellular phone due to its properties, and there are some troubles on the cellular phones that are considered to occur due to static electricity charged in a human body. The static electricity eliminator according to an AC voltage applying method, which is used in a method in which static electricity in a charged product is eliminated by ionizing an atmosphere in the vicinity of the charged product by corona discharge, is expensive, and it requires electric power supply for generating ion gases.
The technique disclosed in JP-A-10-316321 has a problem that a leak of electricity is dangerous and also has a problem that it is difficult to determine whether static electricity is reliably eliminated or not because a static-electricity-eliminated state is not notified.
In the technique disclosed in JP-A-2001-35684, some persons suffer an impact, and, inconveniently, it is required to seek for a metallic portion of a structure, a door of an automobile or the like with which the contact member is to be brought in contact.
In the technique disclosed in JP-A-01-251598, there is involved a problem that an explosion or ignition is liable to be caused when an ignitable gas or organic solvent is present in the vicinity of a place where static electricity is to be eliminated, since static electricity is eliminated by air discharge. The place for use thereof is therefore limited.
The technique disclosed in JP-A-05-174376 requires an expensive ion generating apparatus and requires electric power for generating an ion.
In the technique disclosed in JP-A-2000-262303, it is required to ground the wrist trap, and a wiring (code) is provided for the grounding, which is inconvenient for working.